Organisation and expression of a potato (Solanum tuberosum) protein kinase gene

A 4.3 kb genomic clone from potato ( Solanum tuberosum ) cv. Saturna has been isolated which contains the full coding sequence of a protein kinase gene ( Stpk1 ), 1 kb of 3′ sequence, and the first exon of a neighbouring gene encoding a sucrolytic enzyme. An identical organisation could be detected in a genomic clone carrying a gene that encodes a protein kinase homologue in Arabidopsis thaliana (Hayashida et al., Gene, 121 (1992) 325–330). Southern and RT-PCR analyses indicate that Stpk1 is a single copy gene which is expressed throughout the plant with an increase in transcript abundance in leaf after infection with Phytophthora infestans . While comparisons using the deduced amino acid sequence for STPK1 indicate that it is most closely related to cyclic nucleotide-dependent protein kinases, it contains an additional plant-specific insert of 85 amino acids in the catalytic domain.